1. Field of the Invention
The present invention relates to an endoscopic inspection method for diagnosis through observation of the stained tissue with a high-power observation optical system of an endoscope.
2. Description of the Related Art
Recently, Japanese Unexamined Patent Application Publication No. 2005-640 has disclosed an endoscope including, at a distal end portion thereof, an observation subject region contact-type observation optical system for observing an observation subject region in a state where an objective optical system is brought into contact with the observation subject region, in addition to a normal observation optical system for observing the observation subject region in a state where the objective optical system is not brought into contact with the observation subject region.
Japanese Unexamined Patent Application Publication No. 2006-320366 discloses the endoscope equipped with a super high-power image pickup unit including a super high-power lens unit. The power of the super high-power lens unit is equivalent to that of the histological observation level for observing the cell, gland duct structure and the like, that is, the power level is 200 to 1000 times higher than that of the normal optical microscope. The endoscope allows the super high-power magnified observation and the histological observation with respect to the cell and the gland duct structure by bringing the surface of the distal end of the lens unit into contact with the surface of the tissue. The observation subject region is stained through spray of the dye to the interest region before performing the histological observation such that the outline of the cell is clarified to observe the cell nucleus.
U.S. Pat. No. 6,425,535 discloses the endoscope equipped with means for spraying the dye through the channel.
In the observation subject region such as the stomach or the large intestine, there is mucus on the tissue surface. Therefore in the case the dye is sprayed toward the observation subject region through the treatment instrument channel or the auxiliary water feed channel of the endoscope, the penetration of the dye into the observation subject region is disturbed by the mucus. In other words, it is difficult to allow the observation subject region to be stained as required by the operator during the endoscopic observation. It has been difficult to perform the histological observation in addition to the normal observation.